Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

Mechanisms of metal sorption by biochars: Biochar characteristics and modifications

Development of Biochar-Based Functional Materials: Toward a Sustainable Platform Carbon Material

Recent advancements in supercapacitor technology

Adsorption of heavy metals on conventional and nanostructured materials for wastewater treatment purposes: A review

Fe–Mn binary oxide nanoparticles (FMBON) were reported to be high performance as adsorbent for pollutants removal from aqueous solution. However, there are still limitations in practice application due to the FMBON tend to aggregate into the micro millimeter level. In order to avoid the agglomeration of nanoparticles, this work synthesized the stabilized Fe–Mn binary oxide nanoparticles (CMC-FMBON) by using water-soluble carboxymethyl celluloses (CMC) as the stabilizer. The characteristics of CMC-FMBON and FMBON were measured by using Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and Zeta potential. This work systematically investigated the adsorption capacity of CMC-FMBON for 17β-estradiol (E2) and the influences of external environmental factors on E2 removal. The results indicated that CMC-FMBON had much smaller particles, wider dispersion and larger surface area than the FMBON. CMC-FMBON showed better adsorption performance for E2 than FMBON with the maximum adsorption capacity of CMC-FMBON and FMBON were 124.10 and 98.14 mg/g at 298 K, respectively. The experimental data can be well fitted by the model of pseudo-second-order and Langmuir model. The E2 removal by CMC-FMBON was obviously dependent on pH with the maximum adsorption occurring when the pH was acidic. The removal capacity of CMC-FMBON increased when enhancing ionic strength in solution. Background electrolytes promoted slightly E2 adsorption process whereas the presence of humic acid inhibited the E2 removal. π-π interactions, hydrogen bonds, and oxidation might be responsible for E2 removal. This research suggested that the CMC-FMBON has been considered to be a cost-efficient adsorbent for removing E2 from water.

https://www.mdpi.com/1660-4601/15/10/2218/pdf

Fabrication of Stabilized Fe⁻Mn Binary Oxide Nanoparticles: Effective Adsorption of 17β-Estradiol and Influencing Factors.

The development of novel catalysts for degrading organic contaminants in water is a current hot topic in photocatalysis research for environmental protection. In this study, C3N5 nanosheet/Ag2CO3 nanocomposites (CNAC-X) were used as efficient photocatalysts for the visible-light-driven degradation of methylene blue (MB), and tetracycline hydrochloride (TC-HCl) was synthesized for the first time using a simple thermal oxidative exfoliation and in situ deposition method. Due to the synergistic effect of nanosheet structures, carbon defects, and Z-scheme heterojunctions, CNAC-10 exhibited the highest photocatalytic activity, with photodegradation efficiencies of 96.5% and 97.6% for MB (60 mg/L) and TC-HCl (50 mg/L) within 90 and 100 min, respectively. The radical trapping experiments showed that ·O2− and h+ played major roles in the photocatalytic effect of the CNAC-10 system. Furthermore, intermediates in the photodegradation of MB and TC-HCl were investigated to determine possible mineralization pathways. The results indicated that C3N5 nanosheet/Ag2CO3 photocatalysts prepared in this work could provide an effective reference for the treatment of organic wastewater.

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In Situ Coupling Carbon Defective C3N5 Nanosheet with Ag2CO3 for Effective Degradation of Methylene Blue and Tetracycline Hydrochloride

Effects of biochar-based materials on the bioavailability of soil organic pollutants and their biological impacts.

The amendment effects of biochar on total microbial activity was measured by fluorescein diacetate (FDA) hydrolytic activity, and phytotoxicity in Pb(II)-contaminated soils was examined by the application of 4 different biochars to soil, with rice as a test plant. The FDA hydrolytic activities of biochar-amended soils were much higher than that of the control. The survival rate of rice in lead-contaminated biochar-amended soils showed significant improvement over the control, especially for bamboo biochar-amended soil (93.3%). In addition, rice grown in lead-contaminated control sediment displayed lower biomass production than that in biochar-amended soil. The immobilization of Pb(II) and the positive effects of biochar amendment on soil microorganisms may account for these effects. The results suggest that biochar may have an excellent ability to mitigate the toxic effects of Pb(II) on soil microorganisms and rice. Environ Toxicol Chem 2015;34:1962–1968. © 2015 SETAC

Biochar amendment to lead‐contaminated soil: Effects on fluorescein diacetate hydrolytic activity and phytotoxicity to rice

The invention relates to a preparation method and application of a modified ramie fiber adsorbent. The preparation method comprises the following specific steps: (1) preprocessing a ramie fiber raw material, namely carrying out crushing, sieving, wax removal and alkalization on ramie fiber for later use; (2) compounding anhydride by virtue of a chelating agent, namely adding a chelating agent EGTA into a mixed organic solution of acetic anhydride and an activating agent, carrying out stirring reaction at 65 DEG C, and filtering and drying the solution for later use; (3) modifying the ramie fiber by virtue of the anhydride, namely adding the preprocessed ramie fiber powder with the compounded anhydride into an activating agent solution, carrying out the stirring reaction at 75 DEG C, and washing and drying to obtain the modified ramie fiber adsorbent. The modified ramie fiber adsorbent is good in modifying effect, large in adsorption capacity (the maximal adsorption capacity to a cadmium ion is 159mg/g, and the maximal adsorption capacity to a lead ion is 274mg/g) and is high in adsorption speed, can reach adsorption balance within 10 minutes, can be repeatedly used, has no secondary pollution and is particularly suitable for processing high-concentration industrial wastewater containing heavy metals.

Xiaofei Tan

Papers

Fabrication of Stabilized Fe⁻Mn Binary Oxide Nanoparticles: Effective Adsorption of 17β-Estradiol and Influencing Factors.

In Situ Coupling Carbon Defective C3N5 Nanosheet with Ag2CO3 for Effective Degradation of Methylene Blue and Tetracycline Hydrochloride

Effects of biochar-based materials on the bioavailability of soil organic pollutants and their biological impacts.

Biochar amendment to lead‐contaminated soil: Effects on fluorescein diacetate hydrolytic activity and phytotoxicity to rice

Preparation method and application of modified ramie fiber adsorbent